This invention relates to a sealing means for a spiral wound filtration apparatus such as in reverse osmosis or ultrafiltration apparatus.
At the present time, liquid separation apparatus such as filtration or reverse osmosis apparatus including a spiral wound cartridge are utilized in separation processes for liquids. The spiral wound cartridge is formed by interleaving one or more membrane layers, one or more spacer layers and one or more liquid impermeable layers about a central hollow core which functions as an outlet for permeate. The cartridge includes a sealing configuration which prevents admixture of permeate with either feed or retentate. The cartridge is positioned within a housing wherein feed is introduced axially into the cartridge, retentate is removed axially from the cartridge and permeate is recovered by way of the central hollow core which is in fluid communication with a fluid outlet in a cover which also seals the cartridge within the housing. At the present time, the feed is sealed from the retentate by a chevron-shaped elastomeric seal which is interposed between the outside surface of the cartridge and the inside surface of the housing for the cartridge in a manner to seal the feed inlet from the retentate outlet. An O-ring, spaced apart from the chevron-shaped seal, is positioned between the cover for the housing and the housing to prevent feed leakage from the housing prior to its being passed through the spiral wound cartridge. Unfortunately, the chevron-shaped seal has a tendency to fail under the normal operating conditions of pressure and fluid flow primarily due to incomplete sealing at the inside wall of the housing and the seal surface contacting the inside wall of the housing.
U.S. Pat. No. 4,594,161 describes a seal structure for a reverse osmosis apparatus wherein a seal is effected between a housing for a spiral wound cartridge and a cover for the housing.
Accordingly, it would be desirable to provide a sealing means which prevents a feed liquid from by-passing a liquid separation means prior to being removed as retentate. Such as sealing means would permit more efficient liquid separation processes which utilize a spiral wound separation cartridge.